Paper products are a staple of every day life. Paper products are used as bath tissue, facial tissue, paper toweling, napkins, etc. Typically, such paper products are made by depositing an aqueous slurry of cellulosic fibers from a headbox. The aqueous carrier is removed, leaving the cellulosic fibers to form an embryonic web which is dried to form a paper sheet. The cellulosic fibers may be dried with press felts, by through air drying or by any other suitable means.
A particularly preferred through air drying apparatus utilizes a through air drying papermaking belt having a patterned framework. The framework may comprise an essentially continuous network made of a photosensitive resin with discrete deflection conduits therethrough. The essentially continuous network provides an imprinting surface which densifies a corresponding essentially continuous network into the paper being manufactured.
The discrete, isolated deflection conduits of the through air drying belt form domes in the paper. Other geometries of the framework and deflection conduits are known in the art. For example, the framework and deflection conduits may both be semicontinuous, or the deflection conduits may be continuous and the framework discontinuous.
The domes form low density regions in the paper and improve the caliper, bulk, absorbency and softness of the paper. Through air drying on a photosensitive resin belt has numerous advantages, as illustrated by the commercially successful Bounty.RTM. paper towel, Charmin.RTM. bath tissue and Charmin Ultra.RTM. bath tissue, all sold by the assignee of the present invention.
The through air drying process is preferrably accomplished with some lateral leakage of air within the plane of the belt. The lateral leakage may occur at the backside of the belt, as disclosed in the prior art. Alternatively, the lateral leakage may occur across the top surface of the belt with the present invention.
The present invention provides even softer paper, yet retains the advantages of paper manufactured with the aforementioned photosensitive resin through air drying belts. This is accomplished by providing hinge lines in the imprinting surface of the papermaking belt. This invention further provides paper, including through air dried paper, having improved softness obtained by modifying the high density region of the paper from the teachings of the prior art.